1. Field
The presently disclosed subject matter relates to methods for manufacturing semiconductor light-emitting devices and semiconductor light-emitting devices, and more particularly to the methods for manufacturing the semiconductor light-emitting devices that can provide a high radiating performance and a high alignment accuracy and the semiconductor light-emitting devices having a high radiating performance and a high alignment accuracy which can be used as a light source for lighting units such as a vehicle lamp, etc.
2. Description of the Related Art
Recently, vehicle lamps such a headlight using a semiconductor light-emitting device as a light source have been put to practical use, and therefore have been required for semiconductor light-emitting devices having a high light-intensity. The semiconductor light-emitting devices having a high light-intensity may be accomplished by applying a large current to high-capacity semiconductor light-emitting chips in general. However, when light having a high brightness is emitted by a semiconductor light-emitting device using the large current, because an amount of heat generated from the semiconductor light-emitting device increases, a temperature of the semiconductor light-emitting device may increase due to a self-generated heat of the device.
Accordingly, when the semiconductor light-emitting device is driven by the large current, a light-emitting life may decrease due to a degradation of the semiconductor light-emitting device, which is caused by increasing the temperature of the semiconductor light-emitting device, with decrease in an amount of light emitting because of a decrease of light conversion efficiency, which is caused by increasing the temperature of the semiconductor light-emitting device. As a result, the semiconductor light-emitting device may be difficult to maintain a high reliability and an appropriate amount of the light emitting.
In order for the semiconductor light-emitting device to maintain the high reliability and the appropriate amount of the light emitting, the increase of the temperature due to the self-generated heat of the semiconductor light-emitting device may be required to be prevented by improving a radiating performance of the heat generated from the semiconductor light-emitting device. Thereby, the improvement of the radiating performance may result in a low-power consumption of the semiconductor light-emitting device.
Such a semiconductor light-emitting device is disclosed in Patent document No. 1 (Japanese Patent Application Laid Open JP 2012-165016). FIG. 9 is an explanatory cross-sectional view depicting a first conventional semiconductor light-emitting device, which is disclosed in Patent document No. 1. The first conventional light-emitting device 100 includes: an alumina laminate sheet 82 including a first aluminum sheet 80 and a second aluminum sheet 81; a pair of electrode pads 83 made from a metallic layer, and formed on the second aluminum sheet 81 of the alumina laminate sheet 82;and a pair of lead electrodes 84 made from a metallic layer, formed underneath the first aluminum sheet 80 of the alumina laminate sheet 82, and each of the lead electrodes 84 being electrically connected to a respective one of the electrode pads 83 via a though hole 85 made from a silver (Ag), respectively.
In addition, the first conventional light-emitting device 100 also includes a light-emitting diode (LED) chip 86 having a p-electrode 88 and a n-electrode 89 formed on a light-emitting layer 87, each of the p-electrode 88 and the n-electrode 89 being electrically connected to the respective one of the electrode pads 83 via Au bump 90 and silver paste 91, attached to the alumina laminate sheet 82 using an underfill resin 92, which is disposed between the alumina laminate sheet 82 and a sapphire transparent substrate 93 of the LED chip 86, and thereby light emitted from the light-emitting layer 87 can be emitted via the sapphire substrate 93.
In this case, the pair of electrode pads 83 formed on the second aluminum sheet 81 and the pair of lead electrodes 84 formed underneath the first aluminum sheet 80 in the aluminum laminate substrate 82 may be electrically connected via the though holds 85 including the Ag. Hence, the first conventional light-emitting device 100 may improve a thermal conductivity and a heat resistance thereof.
FIG. 10 is an explanatory cross-sectional view depicting a second conventional semiconductor light-emitting device, which is disclosed in Patent document No. 2 (Japanese Patent Application Laid Open JP 2006-269079). The second conventional semiconductor light-emitting device 110 includes: a red LED chip 111; a green LED chip 112; a blue LED chip 113; a sub mount substrate 114 mounting the red LED chip 111, the green LED chip 112 and the blue LED chip 113 thereon; a wiring board 117 configured to be electrically connected to electrodes of each of the red LED chip 111, the green LED chip 112 and the blue LED chip 113; a metal substrate 116 mounting the sub mount substrate 114 and the wiring board 117 thereon; and a heat sink 115 attached to the metal substrate 116 to radiate heats from generated from each of the red LED chip 111, the green LED chip 112 and the blue LED chip 113.
However, in the first conventional semiconductor light-emitting device 100, the heat generated from the LED chip 86 may radiated in an outer direction of the device 100 by transmitting the heat to each of the p-electrode 88 and the n-electrode 89 of the LED chip 86, the pair of electrode pas 83, the though holes 85 and the pair of lead electrodes 84. The heat must be transmitted to elements having a small cross-sectional area such the Au bump 90 and the though hole 85 in a transmitting pathway between the LED chip 86 and the lead electrodes 84. Accordingly, the first conventional device 100 may be difficult to fully prevent from an increase of temperature caused by a self-generated heat of the LED chip 86, because a thermal resistance in the transmitting pathway may increase and a radiating efficiency may decrease.
In addition, according to the second conventional semiconductor light-emitting device 110, when each of the red LED chip 111, the green LED chip 112 and the blue LED chip 113 is mounted on the sub mount substrate 114, a misalignment of each of the red LED chip 111, the green LED chip 112 and the blue LED chip 113 with respect to the sub mount substrate 114 may occur although alignment means of the LEDs may not be defined. When the sub mount substrate 114 is mounted on the metal substrate 116, a misalignment of the sub mount substrate 114 with respect to the metal substrate 116 may occur due to the similar reason. Therefore, when the conventional semiconductor light-emitting device 110 is used as a light source for vehicle lamps such as a headlight, the vehicle lamps may cause a degradation of light distribution characteristics and the like because of the misalignments.
The above-referenced Patent Documents are listed below, and are hereby incorporated with their English abstracts in their entireties.    1. Patent Document No. 1: Japanese Patent Application Laid Open JP 2012-165016    2. Patent Document No. 2: Japanese Patent Application Laid Open JP 2006-269079
The disclosed subject matter has been devised to consider the above and other problems features and characteristics. Thus, an embodiment of the disclosed subject matter can include a method for manufacturing semiconductor light-emitting devices having a metallic laminate substrate using an electro-painting method that can improve a radiating performance and alignment accuracy by utilizing features of a metallic laminate substrate, while reducing other associated problems of the conventional devices.